<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>jq选择器</title>
  <script src="../js/jquery.js"></script>
  <script>
    console.log($);
    // 页面加载完毕后执行
    $(function() {
      $('<div class="new">four</div>').appendTo('.box')
      $('.child').text('hello')
    })
  </script>
</head>
<body>
  <div class="box">
    <div class="child">one</div>
    <div class="child">two</div>
    <div class="child">three</div>

  </div>
</body>
</html>